The present invention relates to an ink jet print head of the type in which a nozzle plate, a fluid path forming member and an elastically deformable cover member are layered, and pressure generating means are attached to the cover member.
An ink jet print head of the type in which a nozzle plate, a fluid path forming member and an elastically deformable cover member are layered, and pressure generating means, for example, piezoelectric vibrators of a flexure vibration mode, are attached to the surface of the cover member, is known. In the print head, most of the members or constituent elements of the print head are made of ceramics. Accordingly, it is possible to layer the green sheets of those elements and to sinter the layered ones. In other words, these elements may be jointed together without adhesive, and hence there is eliminated a bonding step by adhesive in the manufacturing process of the print head, and the manufacturing process is simplified.
In the print head, as shown in FIG. 32(a), discrete electrodes B, B, . . . , B of piezoelectric vibrators A, A, . . . , A are connected to an external device by a flexible cable C.
To improve the print quality and the printing speed, some type of the print head has an increased number of nozzle holes. In this type of the print head, the discrete electrodes are extremely narrow in width, and the number of them is large. Connection work of these discrete electrodes to a flexible cable C is very difficult. Further, the conductive patterns of the flexible cable C as signal paths connecting an external device to the print head are also considerably narrow. The narrow conductive patterns have high electrical resistance. To feed signals of satisfactorily high level from the external device to the print head through the conductive patterns, a drive circuit of high drive voltage and high power is required.
To solve the problem, there is a proposal as shown in FIG. 32(b). In the proposal, a semiconductor chip D with a drive signal generating function is fastened to the surface of an actuator unit E of the print head and sealed by resin F. The semiconductor chip D must be mounted at a place on the actuator unit E where no piezoelectric vibrators are present. This increases the size of the print head, and requires additional work to connect the signal output terminals of the semiconductor chip D to the discrete electrodes B, B, . . . , B by wires G and G'.
The flexible cable that connects electric signals from the external device to the print head is mounted on the actuator unit in such a way that the cable extends over the arrays of piezoelectric vibrators on the rear side of the actuator unit, and are secured at both the ends in width direction to the terminals connecting to the discrete electrodes on both sides of the actuator unit. Such a mounting of the flexible cable creates some problems. For example, in the case of the loosely mounted flexible cable, if an external force acts on the flexible cable, the flexible cable will come in contact with the piezoelectric vibrators. In this state, the cable suppressively acts on the vibration of the piezoelectric vibrators.